function vec = PolarVec3(theta, phi)
%
%
%        vec = PolarVec3(theta, phi)
%
%
%        Input:
%           -theta: theta angle
%           -phi: phi angle
%
%        Output:
%           -vec: a 3D cartesian direction
%
%     Copyright (C) 2011  Francesco Banterle
% 
%     This program is free software: you can redistribute it and/or modify
%     it under the terms of the GNU General Public License as published by
%     the Free Software Foundation, either version 3 of the License, or
%     (at your option) any later version.
% 
%     This program is distributed in the hope that it will be useful,
%     but WITHOUT ANY WARRANTY; without even the implied warranty of
%     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
%     GNU General Public License for more details.
% 
%     You should have received a copy of the GNU General Public License
%     along with this program.  If not, see <http://www.gnu.org/licenses/>.
%

sinTheta = sin(theta);
vec = [cos(phi) * sinTheta, cos(theta), sin(phi) * sinTheta];

end